Arctic

Description

The stunning, icy landscapes and charismatic wildlife of the Arctic region have captured the imaginations of humans for centuries. The word ‘Arctic’ comes from the Greek word for bear, ‘arctos’, and it is named after the Great Bear (Ursa Major) and Little Bear (Ursa Minor) constellations that appear in the Arctic sky all year round. (1).

The Arctic is not a country or continent, but rather a region at the extreme north of the planet. Roughly, it includes the Arctic Ocean (the world’s smallest ocean) and the surrounding seas, as well as the world’s...

Arctic fact file

Description

The stunning, icy landscapes and charismatic wildlife of the Arctic region have captured the imaginations of humans for centuries. The word ‘Arctic’ comes from the Greek word for bear, ‘arctos’, and it is named after the Great Bear (Ursa Major) and Little Bear (Ursa Minor) constellations that appear in the Arctic sky all year round. (1).

The Arctic is not a country or continent, but rather a region at the extreme north of the planet. Roughly, it includes the Arctic Ocean (the world’s smallest ocean) and the surrounding seas, as well as the world’s largest island, Greenland, and the northern extremities of several countries including Russia, Alaska and Canada (2)(3). The most northerly point of the planet, the North Pole, is located on the continually shifting sea ice of the Arctic Ocean (2).

Much of the Arctic Ocean remains covered in floating sea ice throughout the year (4). However, in spite of the Arctic’s icy reputation, permanent land ice only covers a small area outside of Greenland. The climate of the Arctic is highly variable, both with season and location (4). During the winter months, the sun does not rise above the horizon in the northern reaches of the Arctic, causing temperatures in some areas to plummet to -60 degrees Celsius (1)(5). In contrast, average July temperatures over snow-free land can be much warmer, sometimes reaching up to 20 degrees Celsius (4). The level of precipitation over the Arctic is also highly variable, with some areas receiving as little as 200 millimetres and others well over 1,000 millimetres (4).

Environmental conditions vary dramatically across the Arctic region and, as a result, the Arctic is sometimes divided into the High Arctic and the Low Arctic (4). The typical habitat of the Arctic region is tundra, which is characterised by treeless, grassy plains (5). The High Arctic is generally distinguished by having more severe environmental conditions and an extreme form of Arctic tundra known as polar desert. Polar deserts are typified by having low levels of moisture and therefore scant vegetation cover (4). In the Low Arctic, vegetation cover can be between 80 and 100 percent, with sedges and grasses forming a major component of the tundra, as well as shrubs and some low growing tree species (4).

A characteristic feature of the Arctic tundra is permafrost, or permanently frozen ground (1). The permafrost strongly shapes both the Arctic landscape and the vegetation that can grow there (1). While the permafrost may remain frozen year round in some areas of the High Arctic, in the Low Arctic it has an active top layer that thaws each summer (4). The frozen ground below this active layer acts as an impermeable barrier, leading to the ground becoming waterlogged and forming numerous shallow lakes (4).

Range

The boundary of the Arctic region is not well defined (1). However, in general the Arctic region is said to include the Arctic Ocean and surrounding seas, Greenland, Svalbard, parts of Iceland and also the northern coasts and off-lying islands of Canada, Alaska and Russia (3). Parts of Scandinavia are also often included (3).

Biodiversity

Plants

The sun does not rise at all in the northern reaches of the Arctic from mid-November to late January, contrasting with the almost constant sunlight received in the summer months (5). This dramatic variation in light levels means that the growing season for plants in the Arctic is highly variable, ranging from as little as 60 days, up to 200 days (6).

Despite the extreme conditions, many parts of this remarkable region support an array of plant life (5). In late winter and spring, ice algae blooms along the edge of the retreating sea ice, forming an important part of the Arctic marine ecosystem (1).

There are an estimated 280 species of bird that occur in the Arctic region (1). Some of these breed exclusively in the Arctic, including the brent goose (Branta bernicla), the ivory gull (Pagophila eburnea) and 17 of the 24 species of sandpiper (1)(11). Of the 206 shorebird species known worldwide, 69 of these occur in the Arctic, with many species undertaking long migrations to reach the region (1).

In spite of popular misconception, there are no species of penguin found in the Arctic, with these charismatic birds only occurring in the southern hemisphere (13).

Reptiles and amphibians

Due to the harsh conditions of the Arctic, reptiles and amphibians are generally poorly represented (1). Just four species of lizard occur in the Arctic region, with the viviparous lizard (Lacerta vivipara) being the most northerly occurring reptile species (1)(14).

There is no shortage of invertebrates in the Arctic, with an estimated 3,000 species of insect found in the region. By far the most common group of terrestrial invertebrates found there are in the Order Diptera, or flies (16). Many of the terrestrial species emerge only in the brief Arctic summer, remaining dormant for the rest of the year (16). The larvae of the Gynaephora groenlandica moth can take up to 14 years to mature, surviving the winter in a frozen state (16). Other invertebrates, such as mosquitoes, can complete their development in a single season (16).

In the Arctic Ocean, zooplankton, such as copepods, form an important part of the marine community (3). A number of species of krill also occur in the Arctic, and these provide a plentiful and important food source for fish, seabirds and whales (3).

In total, there are around 450 species of fish that live in the Arctic (1). The most northerly ranging of these is the Arctic charr (Salvelinus alpinus), which occurs in both the marine and freshwater systems of the Arctic (17). The Arctic cod (Boreogadus saida) forms vast shoals, and is specially adapted for a life in the icy waters by having proteins in its blood that act as antifreeze (1)(18).

Threats

Climate change is currently the greatest threat to the Arctic region (1). Changes in global temperatures are likely to have a range of complex impacts on the Arctic region, with some areas predicted to warm and others to cool (1). The effect this will have on many of the unique Arctic ecosystems is largely unknown, though the Arctic sea ice has been shown to have decreased by 14 percent since the 1970s (19). This has already reduced the available habitat for species such as the polar bear, which relies on the presence of the Arctic sea ice to hunt (19).

Overexploitation by humans is another threat faced by numerous species that inhabit the Arctic (1). In the past, traditional methods meant that hunting in the region was largely sustainable (1). However, the advent of commercial methods has caused dramatic population decreases in many fish, whale and bird species (1)(19). Bycatch is also a serious problem, threatening several fish and seabird species in particular (1)(19).

The Arctic region is vulnerable to pollution from a number of sources (1). The development of the oil and gas industries may result in the spillage of chemicals and oil into Arctic waters, while the high number of nuclear reactors in the region has potential to create future radioactive contamination (19). The movement of ocean currents mean that the Arctic seas are also a ‘sink’ for long-range pollutants such as insecticides and heavy metals, including mercury (19).

The construction of roads, use of off-road vehicles, hydropower development and introduction of alien invasive species are all also currently threatening the native species of the Arctic region (1). Many of these activities destroy and fragment habitat, resulting in species having small, isolated populations that are at greater risk of catastrophic events, either natural or man-made (1).

Conservation

The Conservation of Arctic Flora & Fauna (CAFF) is the working group tasked with addressing the issue of conservation in the Arctic, and communicating the findings to the governments and residents of the Arctic nations (20). Conservation strategies implemented by CAFF have already shown success, improving the conservation status of seabirds such as the guillemot (Uria aalge)(1). CAFF have also created the Circumpolar Protected Areas Network (CPAN), which aims to promote the development of a protected network area in the Arctic region (20). Currently, there are 405 protected areas in the Arctic which cover a total of around 2.5 million square kilometres (1).

Another major conservation aim is to regulate fishing, hunting and gathering in the Arctic region, both at the commercial and subsistence level. By involving local people in the planning of wildlife management it is hoped that sustainable methods that conserve both livelihoods and biodiversity can be developed (1).

Future priorities for conservation in the Arctic region include the establishment of PSSAs (Particularly Sensitive Sea Areas) in order to protect vulnerable marine areas from shipping activities (19). It is also hoped that any future development in the Arctic region will use the ‘Conservation First’ principle to conserve vulnerable ecosystems (19).

The future of the Arctic region is very much reliant upon international conservation efforts. Many problems, such as pollution, climate change and the persecution of migratory species, originate in countries far beyond the borders of the Arctic region. Gaps in the knowledge of Arctic ecosystems also need to be filled in order to understand how to best conserve this unique eco-region (1).

immature stage in an animal’s lifecycle, after it hatches from an egg and before it changes into the adult form. Larvae are typically very different in appearance to adults; they are able to feed and move around but are usually unable to reproduce.

Order

a category used in taxonomy, which is below ‘class’ and above ‘family’. All members of an order have characteristics in common.

Tundra

treeless, grassy plains characteristic of Arctic and sub-Arctic regions. They are very cold and have little rainfall.

Zooplankton

tiny aquatic animals that drift with currents or swim weakly in water.

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